I wouldn't give this rumor much consideration.
The Titans wouldn't make such an ignorant move. Fisher is the face of the Titans organization, and he is a great coach. Jeff helped the Titans achieve a record of 8-3 over the final 11 games of the season, and getting rid of him would severely hurt the morale of the team, which would shatter any momentum that might have carried over into 2007.
Besides, the Coach FA pool is very shallow right now, and the Titans wouldn't be able to find a coach that would be able to replace Jeff. This would be a horrible move, and it would upset a lot of fans, including myself. Again, I would be shocked if this rumor had any credibility, as I think that Bud Adams is much too smart to make such an ignorant move.